Issue #20664 has been updated by zverok (Victor Shepelev).
These options should take callables in this proposal. Procs and Methods certainly meet the condition: "Any value that responds to to_proc and returns a Proc object is accepted in these options".
Oh, yeah, sorry, missed this part, focused just on Symbol examples. Interesting, I don’t think we have any API in core like this—accepting anything to convert it `#to_proc` implicitly. Usually when the second callable needed, the agreement is that it should respond to `#call`, not to `#to_proc` (examples: `Proc#>>`, `Enumerator#new`). I am not sure it is “how it should be” (not a lot of APIs like this anyway), but approach with `#to_proc`-able things passed in many keyword arguments seems more Rails-ish. Maybe it is time to accept it. ---------------------------------------- Feature #20664: Add `before` and `until` options to Enumerator.produce https://bugs.ruby-lang.org/issues/20664#change-109528 * Author: knu (Akinori MUSHA) * Status: Open ---------------------------------------- Enumerator.produce provides a nice way to generate an infinite sequence but is a bit awkward to define how to end a sequence. It lacks a simple and easy way to produce typical finite sequences in an intuitive syntax. This proposal attempts to solve the problem by adding these two options to the method: - `before`: when provided, it is used as a predicate to determine if an iteration should end before a generated value gets yielded. - `until`: when provided, it is used as a predicate to determine if an iteration should end until after a generated value gets yielded. Any value that responds to `to_proc` and returns a `Proc` object is accepted in these options. A typical use case for the `before` option is traversing a tree structure to iterate over the ancestors or following/preceding siblings of a node. The `until` option can be used when there is a clear definition of the "last" value to yield. ```ruby enum = Enumerator.produce(File, before: :nil?, &:superclass) enum.to_a #=> [File, IO, Object, BasicObject] enum = Enumerator.produce(3, until: :zero?, &:pred) enum_to_a #=> [3, 2, 1, 0] ``` ---Files-------------------------------- 0001-Add-before-and-until-options-to-Enumerator.produce.patch (10.7 KB) -- https://bugs.ruby-lang.org/